How to start a thread (inline)

[DiamonDogX]

I am aware that to execute something in a separate thread, one can simply extend QThread, implement run(), and write the pertinent code in the run method. But is there a way to execute an arbitrary block of code in a separate thread w/o having to create a whole new class? For example, maybe when I click a button I want a task to be executed in a separate thread, etc. Thanks.

[lni]

I am aware that to execute something in a separate thread, one can simply extend QThread, implement run(), and write the pertinent code in the run method. But is there a way to execute an arbitrary block of code in a separate thread w/o having to create a whole new class? For example, maybe when I click a button I want a task to be executed in a separate thread, etc. Thanks.

Use OpenMP

#pragma omp parallel default(none) shared(n,a,b,c,d) private(i)
{ 
  #pragma omp for nowait
  for (i=0; i<n-1; i++)  b[i] = (a[i] + a[i+1])/2;
 
  #pragma omp for nowait
  for ( i=0; i<n; i++ ) d[i] = 1./c[i];
 
} /* -- End of parallel region -- */

#pragma omp parallel default(none) shared(n,a,b,c,d) private(i)
{ 
  #pragma omp for nowait
  for (i=0; i<n-1; i++)  b[i] = (a[i] + a[i+1])/2;

  #pragma omp for nowait
  for ( i=0; i<n; i++ ) d[i] = 1./c[i];

} /* -- End of parallel region -- */

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Or google search for QtConcurrent

[wysota]

See QRunnable and QThreadPool or better yet QtConcurrent::run.

[DiamonDogX]

While we're on the subject, if I am executing code in another thread (i.e. a thread that is not the UI thread), is there a way to manually execute a piece of code on the UI thread?

[wysota]

Yes. Either post an event to the main thread and catch it from within QObject::customEvent() of the object living in the main thread or use QMetaObject::invokeMethod() with Qt::QueuedConnection as the last parameter. The method you call has to be a slot.